Strenghtening word that hasn't been used

When I do some lesson practice, I use words that first come to my head. In many cases there are many possibilities that could be used.

What surprised me today was that no matter which word I actually use, the strenghtened word is the one from best solution. For example in French lesson, I had expression with "weird" and I used "bizzare". But in the end I could see that the word "etrange" (with accent) was strenghtened...

I think this is... bizzare and in fact make my words strength a bit fake. I think it is an issue.